<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Form JS test</title>
    <script>
        function validateForm() {
            var name_text = document.forms["form_test"]["fname"].value;
            if (name_text == null || name_text == "") {
                alert("请输入您的名字");
                return false;
            }
        }

    </script>
</head>
<body>
<form name="form_test" action="http://bigdata19:5005/apk/version_update" onsubmit="return validateForm()" method="get">
    请输入名字：<input type="text" name="fname"/><input type="submit" value="提交"/>

</form>
</body>
</html>